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4531. Southern red high proper motion objects
ID:
ivo://CDS.VizieR/J/A+A/440/1061
Title:
Southern red high proper motion objects
Short Name:
J/A+A/440/1061
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of spectroscopic follow-up observations for a sample of 71 red objects with high proper motions in the range 0.08-1.14 arcsec/yr as detected using APM and SuperCOSMOS Sky Surveys (SSS) measurements of multi-epoch photographic Schmidt plates. Red objects were selected by combining the photographic BjRI magnitudes with 2MASS near-infrared JHKs magnitudes. Some 50 of the 71 spectroscopically classified objects turn out to be late-type (>M6) dwarfs and in more detail, the sample includes 35 ultracool dwarfs with spectral types between M8 and L2, some previously reported, as well as five M-type subdwarfs, including a cool esdM6 object, SSSPM J0500-5406. Distance estimates based on the spectral types and 2MASS J magnitudes place almost all of the late-type (>M6) dwarfs within 50pc, with 25 objects located inside the 25pc limit of the catalogue of nearby stars. Most of the early-type M dwarfs are located at larger distances of 100-200pc, suggesting halo kinematics for some of them. All objects with Halpha equivalent widths larger than 10 Angstroms have relatively small tangential velocities (<50km/s). Finally, some late-type but blue objects are candidate binaries.
4532. Southern Sky Redshift Survey
ID:
ivo://CDS.VizieR/J/AJ/116/1
Title:
Southern Sky Redshift Survey
Short Name:
J/AJ/116/1
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report redshifts, magnitudes, and morphological classifications for 5369 galaxies with m_B_<=15.5 and for 57 galaxies fainter than this limit, in two regions covering a total of 1.70 sr in the southern celestial hemisphere. The galaxy catalog is drawn primarily from the list of nonstellar objects identified in the Hubble Space Telescope Guide Star Catalog (GSC). The galaxies have positions accurate to ~1" and magnitudes with an rms scatter of ~0.3mag. We compute magnitudes (m_SSRS2_) from the relation between instrumental GSC magnitudes and the photometry by Lauberts & Valentijn. From a comparison with CCD photometry, we find that our system is homogeneous across the sky and corresponds to magnitudes measured at the isophotal level ~26mag/arcsec^2^. The precision of the radial velocities is ~40km/s, and the redshift survey is more than 99% complete to the m_SSRS2_=15.5mag limit. This sample is in the direction opposite that of the CfA2; in combination the two surveys provide an important database for studies of the properties of galaxies and their large-scale distribution in the nearby universe.
4533. Southern sky survey of 1355 spiral galaxies
ID:
ivo://CDS.VizieR/J/ApJS/81/413
Title:
Southern sky survey of 1355 spiral galaxies
Short Name:
J/ApJS/81/413
Date:
21 Oct 2021
Publisher:
CDS
Description:
The data from photometric and spectroscopic observations of 1355 southern spiral galaxies are presented and used to determine their distances and peculiar velocities via the Tully-Fisher (TF) relation. I-band CCD surface photometry was carried out using the 1-m and 3.9-m telescopes at Siding Spring Observatory. H-alpha rotation curves for 965 galaxies and 551 H I profiles are presented. The physical parameters, photometric and velocity data, distances, and peculiar velocities of the galaxies are presented in tabular form. The mean distance, systemic velocity, and average peculiar velocity of 24 clusters in the sample are given. TF diagrams are presented for each cluster.
4534. Southern ultracool dwarfs in young moving groups
ID:
ivo://CDS.VizieR/J/MNRAS/402/575
Title:
Southern ultracool dwarfs in young moving groups
Short Name:
J/MNRAS/402/575
Date:
21 Oct 2021
Publisher:
CDS
Description:
We associate 132 low-mass ultracool dwarfs in the southern hemisphere as candidate members of five moving groups (MGs) using photometric and astrometric selection techniques. Of these objects, we present high-resolution spectroscopy for seven candidates and combine these with previous measurements from the literature to determine spectral types and radial velocities. We thus constrain distance and space motion spectroscopically, allowing the kinematic membership of the MGs to be assessed. Possible membership of MGs has allowed ages and metallicities to be constrained for these objects and evolutionary models have been used to estimate their mass. We estimate that up to ~75 of our candidate MG members should be genuine, and discuss future work that will confirm and exploit this major new sample.
4535. South Galactic cap MCT blue objects
ID:
ivo://CDS.VizieR/J/AJ/119/241
Title:
South Galactic cap MCT blue objects
Short Name:
J/AJ/119/241
Date:
21 Oct 2021
Publisher:
CDS
Description:
Results for the south Galactic cap region of the Montreal-Cambridge-Tololo survey of blue subluminous stars are presented. This region overlaps the 840 deg^2^ region studied almost three decades ago by Slettebak & Brundage (1971AJ.....76..338S). We present a list of equatorial coordinates, photographic photometry, and spectroscopic identifications, as well as finding charts, for 188 blue objects [(U-B)_pg_<=-0.6] brighter than B_pg_=16.5 in this area. Completeness of the survey and comparisons with other similar efforts are discussed.
4536. Spaghetti Survey
ID:
ivo://CDS.VizieR/J/AJ/120/2496
Title:
Spaghetti Survey
Short Name:
J/AJ/120/2496
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Spaghetti project is a pencil-beam photometric and spectroscopic survey designed to identify structure in the Galactic halo. Four-color stellar photometry in the modified Washington filter set is used to identify halo stars for spectroscopic observations. The filters include C, M, T2 and DDO51. The fields in the survey are chosen from high Galactic-latitude positions with low reddening and no stars as bright as SAO stars. Thus far we have imaged 134 fields covering a total area of 52deg^2^. These fields are listed in table1.dat. Due to weather, the only fully calibrated photometry was measured from images taken with the BTC ccd mosaic camera on the CTIO 4m telescope in April 1999. Table4.dat lists these stars from the 53 BTC fields, which covers a total area of 13 square degrees. These data include only those stars whose measurement errors are less than 0.04 in all four filters (32655 total stars). Photometric measurements of stars in the other fields will be published as soon as they can be fully calibrated. See <GCPD/48> for a short description of the Washington Photometric system.
4537. S-PASS & NVSS bright extragalactic radio sources
ID:
ivo://CDS.VizieR/J/ApJ/829/5
Title:
S-PASS & NVSS bright extragalactic radio sources
Short Name:
J/ApJ/829/5
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a polarization catalog of 533 extragalactic radio sources that have a 2.3GHz total intensity above 420mJy from the S-band Polarization All Sky Survey, S-PASS, with corresponding 1.4GHz polarization information from the NRAO VLA Sky Survey, NVSS. We studied the selection effects and found that fractional polarization, {pi}, of radio objects at both wavelengths depends on the spectral index, the source magnetic field disorder, the source size, and depolarization. The relationship between depolarization, spectrum, and size shows that depolarization occurs primarily in the source vicinity. The median {pi}_2.3_ of resolved objects in NVSS is approximately two times larger than that of unresolved sources. Sources with little depolarization are ~2 times more polarized than both highly depolarized and re-polarized sources. This indicates that intrinsic magnetic field disorder is the dominant mechanism responsible for the observed low fractional polarization of radio sources at high frequencies. We predict that number counts from polarization surveys will be similar at 1.4GHz and at 2.3GHz, for fixed sensitivity, although ~10% of all sources may currently be missing because of strong depolarization. Objects with {pi}_1.4_~{pi}_2.3_>=4% typically have simple Faraday structures, so they are most useful for background samples. Almost half of flat-spectrum ({alpha}>=-0.5) and ~25% of steep-spectrum objects are re-polarized. Steep-spectrum, depolarized sources show a weak negative correlation of depolarization with redshift in the range 0<z<2.3. Previous non-detections of redshift evolution are likely due the inclusion of re-polarized sources as well.
4538. Spatial distribution of brown dwarfs in Taurus
ID:
ivo://CDS.VizieR/J/ApJ/645/676
Title:
Spatial distribution of brown dwarfs in Taurus
Short Name:
J/ApJ/645/676
Date:
21 Oct 2021
Publisher:
CDS
Description:
By combining photometry from the 2MASS Point Source Catalog and the USNO-B1.0 catalog with optical and infrared spectroscopy, I have performed a search for young brown dwarfs in an area of 225deg^2^ encompassing all of the Taurus star-forming region (tau~1Myr). From this work, I have discovered 22 new members of Taurus, 5 of which were independently found by Guieu and coworkers (2006, Cat. <J/A+A/446/485>). Sixteen of these new members have spectral types later than M6 and thus are likely to be brown dwarfs according to the theoretical evolutionary models of Chabrier and Baraffe (2000ApJ...542..464C). After adding these new members to the previously known members of Taurus, I have compared the spatial distributions of stars and brown dwarfs across the entire region. I find no statistically significant difference between these two distributions. Taurus does not contain the large, extended population of brown dwarfs that has been predicted by some embryo ejection models for the formation of brown dwarfs. However, these results are consistent with other ejection models, as well as models in which stars and brown dwarfs share a common formation mechanism.
4539. Spatial distribution of magnetic CP stars
ID:
ivo://CDS.VizieR/J/other/Ap/46.234
Title:
Spatial distribution of magnetic CP stars
Short Name:
J/other/Ap/46.23
Date:
21 Oct 2021
Publisher:
CDS
Description:
On the basis of analysis of original publications and our own measurements a Cataloque of magnetic chemically peculiar (CP) upper-main sequence stars has been established. The sample includes 211 magnetic CP stars with magnetic fields ranging from hundreds of gauss to dozens of kilogauss, for 49 of them the surface magnetic field (B_e_) has been measured from the Zeeman splitting. The CP stars may be divided into 3 groups: reversing stars (table3, longitudinal field B_e_ changes its sign), non-reversing (table4, B_e_ keeps the same sign), and poorly studied stars.
4540. Speckle holography of binary systems with OAN-SPM
ID:
ivo://CDS.VizieR/J/AJ/160/9
Title:
Speckle holography of binary systems with OAN-SPM
Short Name:
J/AJ/160/9
Date:
08 Dec 2021
Publisher:
CDS
Description:
We present our first results of multiband Speckle Holography of components of visual double stars. The observations were performed during 2019-April at the 2.1m telescope at the Observatorio Astronomico Nacional at Sierra de San Pedro Martir (Mexico). We have observed 190 double stars with separation between 3" and 5". The position angle, separation and magnitude difference in three broadband optical filters (VRI) for these systems are provided. For 15 systems we found different interesting features, we have identified a close component for 9 of those systems; 5 of them are newly discovered. In the remaining 6 systems, although unresolved, we found elongations that we have been able to derive astrometric parameters if proven to be a (newly discovered) close component. This corresponds to about 8% of the sample presenting a certain feature in one of the components and about 5% of the sample having a confirmed close component.